In her garden for WWF (World Wildlife Fund), Fiona Stephenson attempts to recreate the “meditative magic” of a chalk stream, basing her garden on a stretch of the River Itchen in Hampshire. In part, the challenge has been to copy the natural habitat with the requisite accuracy – achieving sufficient flow of crystal-clear water (“we needed much bigger pumps than we expected”), recreating the stony bottom and coaxing the underwater plants to flourish in the garden environment.

“You can’t be entirely true to nature. Plants growing in fast-flowing water will actually assume different shapes. But what I’m trying to do is evoke the special feeling of this environment – its extraordinary quality of calm and quiet. In all my gardens I aim to deliver a sense of peace and wellbeing, of being at one with nature. This isn’t that different, but it’s much harder to manipulate a naturalistic landscape.”

The planting mixes wild plants such as flag iris, meadowsweet and brooklime (Veronica beccabunga) with “troll-like” weeping sedge Carex pendula and loose drifts of chalk lovers such as Knautia, Veronicastrum, yellow scabious and white rosebay willowherb – “garden plants, but with an air of wildness about them”.

The garden aims to draw attention to the plight of Britain’s over-abstracted rivers, so the design also incorporates a range of “hidden messages” to promote water saving.

Fifty metal spheres by sculptor Ian Gill are arranged in lines, recalling a herringbone drainage system. “These equate to different volumes of water used in our everyday lives, such as taking a bath or brushing our teeth,” explains Fiona, “water that is lost to the stream.” To ram the point home, the stream empties into an enormous plughole.

“I hope people will experience the garden first as a piece of nature, and then discover the element of theatre – they’ll respond to the metaphors in the landscape, and understand why they’re there.” Don’t forget to look out for the panda.